It is interesting to note that much of that virulent hatred of the Japanese displayed by Halsey was for the benefit of the US public through the media. In private conversations, it was said he didn’t speak of the Japanese in that fashion other than to call them “Nips” or “Japs”.
Halsey had apparently made statements that said he did it because he understood it was what people needed to hear in 1941 and 1943, when the chips seemed somewhat down for a period.
I personally don’t fault him for it. It was war.